The European Space Agency (ESA) shared the story of how its engineers saved the mission from peril after a micrometeorite strike, equipment failure, and a severe solar storm.
It has been more than ten years since ESA’s Gaia observatory was launched from Kourou aboard a Russian Soyuz spacecraft and placed into orbit around the second Sun-Earth Lagrangian point (L2), about 1.5 million kilometres from Earth. Its mission is to monitor the positions and movements of stars and exoplanets orbiting around them.
According to the ESAGaia has identified 214 potential exoplanets and can observe approximately 3,400 stars per second.
It was originally designed for a six-year mission, but as is often the case, it outlived initial expectations. Engineer’s Estimate The probe is scheduled to run out of cryogenic gas propellant, which is essential for precise pointing, during the second quarter of 2025. The mission will then move into a post-operations phase, scheduled for completion on December 31, 2030.
But it nearly ended sooner than planned: Earlier this year, the probe was hit by a micrometeorite, damaging the probe’s protective cover. Though Gaia is designed to withstand such impacts, this time the impact came at just the right angle and speed to cause damage.
The damage caused what little sunlight there was to occasionally interfere with the spacecraft’s instruments.
While engineers were working on the problem, Gaia suffered a failure of its charge-coupled device (CCD). “1 billion pixels” The camera uses 106 CCDs to convert light into an electrical signal. While the cause has not been conclusively proven, it has been suggested that the malfunction could be caused by a blast of high-energy particles from the sun, which could potentially damage social media. A shot of a green and purple sky.
Gaia was designed to cope with radiation, but “the storm may have been the final blow for the spacecraft’s ageing hardware,” according to the ESA.
The failed CCD was essential for Gaia to confirm its detection of stars, and with that functionality gone, the probe began recording thousands of false positives.
“Gaia typically transmits more than 25 gigabytes of data to Earth each day, but this amount would be much higher if the spacecraft’s on-board software had not initially eliminated the false star detections,” said Edmund Serpell, Gaia spacecraft operations engineer at ESOC.
Sending a crew to fix the spacecraft isn’t possible; it’s physically impossible to do so 1.5 million kilometers away. Instead, engineers tweaked the software, essentially changing the threshold at which the observatory identifies a faint point of light as a star. The change dramatically reduced false positives caused by light leaks and CCD problems.
Gaia probably has less than a year of precise direction before it runs out of thrust, but that year could yield many discoveries. So we raise a glass to the ingenuity and determination of the engineering team that saved the spacecraft.®
